-
本文应用变分原理研究了电磁复合聚焦-偏转球面阴极透镜的相对论象差理论。在考虑阴极面逸出电子具有一定的初能量和初角度分布,物场和象场弯曲以及阴极面上磁场和横向电场不为零的情况下,导出了任意理想象面上的一级近轴横向象差和包括色球差在内的全部三级几何横向象差,以及各种特殊类型象差系数的明显表达式。本文导出的象差公式不仅普遍适用于宽束和细束阴极透镜,而且普遍适用于相对论或非相对论,阴极和屏为球面或平面时的各种情况。本文以复数描写轨迹,用矩阵表示象差,形式简洁,适合于计算机计算。In the present paper, by means of the variational principle, the relativistic aberration theory for a combined electromagnetic foeusing-deflection system possessing a spherical cathode lens is studied. We have discussed the following general cases: electrons emitted from the cathode possess definite energy and angular initial distributions; the objective and image fields have finite curvatures; the cathode is situated in both magnetic and transversal electric fields. For these general cases the general formulae of aberration coefficients for first and third order transversal geometrical and chromatic aberrations on any ideal image plane are given in explicit form. The above-mentioned aberration coefficient formulae can be applied to the following eases: either the wide electron beam system or the narrow electron beam.system; either the relativistic or the non-relativistic electron optical system; either the cathode or the screen having the spherical or the planar shapes. In the present work, the electron trajectories are described in the complex form. The aberrations are expressed in the matrix form, and are thus suitable for computer computations.
计量
- 文章访问数: 7041
- PDF下载量: 627
- 被引次数: 0